Usage: often capitalized 2d P
Etymology: Middle English; from its originating in Paris, France
1. : a fine white powder consisting essentially of the hemihydrate of calcium sulfate CaSO 4 . 1/2H 2 0 or 2CaSO 4 .H 2 0 that is made by calcining gypsum until it is partially dehydrated, that forms with water a paste which soon sets, and that is used chiefly for casts and molds, building materials (as plasters, tile, blocks, moldings, and stuccowork), and for surgical bandages — called also calcined gypsum
2. : native gypsum